From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [PATCH] xen/pv-on-hvm kexec: add xs_reset_watches to shutdown watches from old kernel Date: Mon, 15 Aug 2011 09:21:16 -0400 Message-ID: <20110815132116.GA15335@dumpdata.com> References: <4b483f4fa715566847b5.1313397256@probook.site> <20110815092530.GA3001@aepfle.de> <20110815125306.GA11127@dumpdata.com> <20110815125958.GA4795@aepfle.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20110815125958.GA4795@aepfle.de> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Olaf Hering Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org On Mon, Aug 15, 2011 at 02:59:58PM +0200, Olaf Hering wrote: > On Mon, Aug 15, Konrad Rzeszutek Wilk wrote: > > > On Mon, Aug 15, 2011 at 11:25:30AM +0200, Olaf Hering wrote: > > > Add new xs_reset_watches function to shutdown watches from old kernel after > > > kexec boot. The old kernel does not unregister all watches in the > > > shutdown path. They are still active, the double registration can not > > > be detected by the new kernel. When the watches fire, unexpected events > > > will arrive and the xenwatch thread will crash (jumps to NULL). An > > > orderly reboot of a hvm guest will destroy the entire guest with all its > > > resources (including the watches) before it is rebuilt from scratch, so > > > the missing unregister is not an issue in that case. > > > > So this patch replaces the big patch series you sent some while ago? > > [I've one of your patches in my tree, but I wasn't sure about the other > > ones] > > No, there are 3 other patches required: > > xen/pv-on-hvm kexec+kdump: reset PV devices in kexec or crash kernel > xen/pv-on-hvm kexec: rebind virqs to existing eventchannel ports > xen/pv-on-hvm kexec: prevent crash in xenwatch_thread() when stale watch events arrive > > I will send them once we settled on a way to reset the watches. Ok. > > Which one did you already apply? commit 6b71c52e7f848e2c9f804e175215e5965ea90d32 Author: Olaf Hering Date: Thu Jul 28 15:23:03 2011 +0200 xen: use static initializers in xen-balloon.c There is no need to use dynamic initializaion, it just confuses the reader. Switch to static initializers like its used in other files. Signed-off-by: Olaf Hering [v2: Rebased on v3.0] > > > If the xenstore does not have the patch for this, what is the > > error code? Is it ENOSYS? If we get that can we not print this message? > > Or perhaps print: > > "Yikes! We can't reset the watches. Potential crash immienient" > > or something similar. > > Now that you mention it, the return code should be checked and ENOSYS > should be filtered to not print the warning on a host without the > updated xenstored. I will update that part of the patch. ok. > > Olaf